Short-tailed Shearwater
Short-tailed Shearwater
Ardenna tenuirostris
At a Glance
This dark, narrow-winged seabird occurs in large flocks over cold waters. It is very similar to the Sooty Shearwater and, like that species, is a visitor from far to the south. Short-tailed Shearwaters nest only around Australia, but in the northern summer they may penetrate north past the Bering Strait. Generally found off Alaska in summer, farther south off west coast in winter.
All bird guide text and rangemaps adapted from by Kenn Kaufman© 1996, used by permission of Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Category
Gull-like Birds, Shearwaters and Petrels
IUCN Status
Least Concern
Habitat
Open Ocean
Region
Alaska and The North, California, Northwest, Western Canada
Behavior
Flap/Glide
Population
15.000.000
Range & Identification
Migration & Range Maps
Moves north through western Pacific in April and May, concentrating off southern Alaska in summer, with some moving north through Bering Strait to Arctic Ocean. Breeders move south again in August and September, crossing tropical waters rapidly. Nonbreeders may remain off Pacific Coast of North America all year; occurs off California mainly in our winter months.
Description
17" (43 cm). W. 40 (102 cm). Much like Sooty Shearwater, not always identifiable. Tends to have shorter bill, rounder head, steeper forehead. Underside of wings often uniform, medium gray to pale gray, without white flash of Sooty.
Size
About the size of a Crow, About the size of a Mallard or Herring Gull
Color
Brown, Gray, White
Wing Shape
Long, Narrow, Pointed, Tapered
Tail Shape
Pointed, Rounded, Wedge-shaped
Songs and Calls
Silent at sea.
Call Pattern
Flat, Undulating
Call Type
Raucous, Scream
Habitat
Open ocean. Concentrations at sea are over continental shelf and around upwellings in cool waters. Breeds on islands close to shore and locally on Australian mainland, where grass and shrubs cover soil soft enough for excavating nesting burrows.
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Behavior
Eggs
One. White. Incubation is by both sexes, 52-55 days.
Young
Both parents feed young, visiting at night, feeding by regurgitation. Feeding visits become less frequent as chick matures. Adults then abandon young, and it goes to sea 82-108 days after hatching.
Feeding Behavior
Forages mostly by diving from surface of water or by plunging from a few feet above surface, swimming underwater by rowing with wings; may dive as deep as 60 feet below surface. Sometimes forages in association with whales or dolphins.
Diet
Mostly fish, crustaceans, squid. Diet varies with region, but may include many small fish; crustaceans, including amphipods and euphausiid shrimp; small octopus and squid. Also some marine worms, jellyfish, insects, other items.
Nesting
Breeds only around southern and eastern Australia. Nesting season extends from September to April. First breeds at age of 5-8 years. Nests in colonies on islands and locally on mainland, with most activity in colony at night. Nest: Sites are in burrows dug in soil under grass or scrub; both sexes help to excavate burrow, and same site may be used for several years. Nest chamber at end of burrow may be bare or lined with grasses.
Climate Vulnerability
Conservation Status
Total numbers estimated at more than 20 million, although declines have been noted recently in some areas.